As it is known, the actual safety regulations require to put in security conduits, ducts, pipelines, systems, machines and similar equipments which are subject in their operation to high pressures and stresses, typically due to the high pressure of a fluid, such as air, oil, water, steam, which is present and circulates in these conduits, pipes, systems, machines and equipments.
Among these regulations there are cited in particular the EN ISO 4413, the BSI and European standards, and the Atex Directive.
In order to comply with these safety regulations, it is known, in the actual technique, to provide and install, in the areas where these conduits, pipes, pipelines, systems, equipments, subject to high pressures, have connections or joints between the respective parts, special safety devices that have the function, in case of breaking, burst, explosion or any other trouble in these connection areas, to retain the parts that constitute these connections.
Therefore, in this way it is prevented, in such event, that the parts of these connections become detached from the other parts and for instance are expelled violently, with the risk of causing further and more severe damages than those already caused by the rupture and the breakage of the conduit, pipe and equipment subject to pressure.
One of these known safety devices, indicated with DS, also often called in the field with the term “whip check”, which has had a significant diffusion in the market and which continues to be widely used, is shown by the photographs of FIGS. 6A and 6B.
In particular, with reference to FIG. 6A, this device DS, known, includes a little flexible metal cable or rope, indicated with COR, which form, at the two opposite ends of the device DS, two respective eyelets, in turn indicated with O1 and O2, which are provided to be attached and tightened on two parts, connected to each other, of the conduit, piping or equipment under pressure to be secured by means of the device DS.
A helical spring MOL is fitted externally on the flexible metal cable COR to confer a certain elasticity to the safety device DS and is adapted to cooperate with two guides G1 and G2, within which the cable COR can slide freely, to facilitate the closure and the tightening of the two eyelets O1 and O2 against the two parts of the connection present in the conduit, piping or equipment, under pressure, to be secured by means of the device DS.
Therefore, in the application and use of this known safety device DS, when, due to the pressure of the circulating fluid, a rupture or a burst or an explosion or any other trouble occurs in the connection area between the two parts of the conduit, pipeline and equipment under pressure, to which the safety device DS was attached, these parts are appropriately retained by the device DS.
In this way it is avoided that the rupture or burst of the connection produces further negative effects, in addition to those that are already produced by the breaking or by the explosion itself, and in particular it is avoided that pieces, of the connection that is broken or exploded, are expelled and ejected, which could cause considerable damage and also be dangerous for the people working in the area of these conduits, pipes and equipments under pressure.
For clarity, the photographic images of FIG. 6B—sections (a)÷(d) show how the safety device DS is initially prepared in order to be then attached to a structure or system under pressure to be put in safety.
In particular these photographic images show one of the guides G1 and G2 of the device DS, while it is made to slide manually by an operator along the cable COR in order to adjust the amplitude of the corresponding O1 eyelet, by means of which the safety device DS is subsequently attached to the two parts of the connection present the pressurized system to be secured.
As can be clearly observed from these images, the cable COR of this safety device DS is free to slide in these guides G1, G2, i.e. without the cable COR being subject, while sliding in the guide to adjust the eyelet, to any real and effective force of friction, for example defined by a given calibrated tightening force that is applied by the guide G1 or G2 to the same cable COR.
Also the photographic images of FIG. 6B—section (e)÷(h) show the known safety device DS when it is attached, by mean of its two eyelets O1 and O2, to two parts, indicated with P1 and P2 and constituted in particular by a hydraulic pump and a tube or pipe suitable for conveying fluids under pressure, of a system under pressure to be secured in the connection area between these two parts P1 and P2.
However this safety device or whip check DS, known, has, despite having had a wide use, some drawbacks and limitations that are not negligible and deserve attention in order to remedy them.
In particular, the safety device DS, though having the capability of retaining the two connected parts in case of breakage and/or burst in the area of their connection, does not appear able to provide an effective damping action, i.e. an action capable of dampening efficaciously the energy and high dynamic forces which necessarily are generated when any of these events occurs.
It follows that, in case of breakage and/or burst, the parts of the connection of the pipe or the conduit under pressure, though being put in safety and therefore retained by the security device known DS, are subject, because of the high energy which develops and is released in these critical events, to relevant and strong dynamic and impulsive stresses, often unpredictable, which can cause further and additional damages in the pipe and may even create a dangerous situation for people who work in the vicinity of the pipe under pressure.
For reference, it is also mentioned patent document U.S. Pat. No. 4,317,257 that concerns a device designed to be used, in combination with a suitable traction device, to tear the skin from the carcass of a dead animal.
In particular, this device, known from U.S. Pat. No. 4,317,257, comprises a flexible cable; a pair of sliding sleeves which house and fold the two end portions of the flexible cable so as to form two eyelets; and two terminals or end stops which are fixed to the two ends of the cable to prevent the slipping of these ends from the sleeves.
In use, this device is preliminarily attached at one side, with a respective first eyelet, to a zone of the skin of the carcass of the dead animal and at the other side, with the second eyelet, to the traction device, by sliding the two terminals along the flexible cable of the device so as to tighten the two eyelets respectively on the skin of the animal carcass and the traction device.
Then the traction device is activated so as to pull and strain the flexible cable of the device, and thus tear the skin from the animal carcass.
But this device, usable for skinning the carcass of a dead animal, clearly concerns a technical field which is very far and different from that of the safety devices for piping and equipments in pressure, and correspondingly implies a use which is significantly different and not comparable with that of the safety device, with a sliding cable, proposed by the current invention.
Furthermore, there is still mentioned document US 2015/026930 A1 that relates to a safety device usable for slinging and securing a line, typically constituted by a hydraulic line or pipeline subjected to high pressure by a fluid flowing in it.
In particular this device, known from US 2015/026930 A1, comprises a flexible cable which has an end portion which is closed and bent on itself by means of a closure device, in turn consisting of two threaded sleeves, suitable to be screwed between them, that receive the cable, so as to form an eyelet or loop at an end of the device, while the other end portion of the cable is not bent but is free.
In use, the loop formed by the cable of this safety device is tightened around the pipeline to be secured, by sliding the cable into the closure device and then screwing the respective two sleeves so as to fix firmly the closure device with respect to the cable and therefore prevent any loosening of the loop tightened around the pipeline, while the free end of the cable is fixed to a fixed structure.
Therefore, in case of explosion or trouble in the area of the pipeline, the device acts to retain the exploded pipe through the loop that is tightened around it, so as to avoid further damages.
However this device, known from US 2015/026930 A1, though being specifically provided for securing a pipeline in pressure and preventing further damages in the event of burst of the pipeline, is not free from some limitations and drawbacks that need to be overcome.
For example, this device has a certain cost, since the respective closure device consists of two parts screwed to each other, and consequently also a mounting on the pipeline which is not immediate and rapid, since implying the screwing of the two parts of the closure device to fix the latter to the cable and tighten the loop firmly around the pipeline to be secured.
Furthermore, the fact that the loop of the device is firmly tightened around the pipeline to be secured does not allow a sliding of the cable, in case of intervention of the device for retaining the exploded pipeline, and therefore limits the capacity of the device of absorbing and damping the energy generated by the explosion of the pipeline.
Embodiments of cable safety or security devices designed to secure connections and joints of conduits and pipelines under pressure, by attaching the safety device to two parts, connected to each other, which form the connection to be secured, are also known from U.S. Pat. No. 3,813,733 and EP 1 891 364 B1.
Finally, additional devices, of the type comprising a flexible cable which is bent and closed on itself, at its two end portions, by two corresponding sleeves or clamps which receive the flexible cable, so as to form two eyelets, wherein these two eyelets, formed at the ends of the device, are suitable to be mounted around two generic separated parts for attaching and connecting them together, for various purposes, are described in documents U.S. Pat. No. 4,529,240 and US 532.242.